# in struct (index-of 2 {:a 1 :b 2 :c 3 :d 2} ) # => :b # in table (index-of 2 @{:a 1 :b 2 :c 3 :d 2}) # => :b # in array (index-of 6 @[4 5 6 7 8 9] ) # => 2 # in tuple (index-of 2 [1 2 3 4]) # => 1